This invention relates to a method for manufacturing a superconducting magnet and, more particularly, to a method for manufacturing a superconducting magnet in which the windings of the superconductor are made rigid by a bonding agent.
Superconducting coils made of a superconductor wound into a coil are relatively easily quenched at a relatively small current. The reason for this is considered to be an irregular wire movement of a conductor portion of the superconductor forming a coil due to an electromagnetic force acting between the superconductors. When the superconductor moves, it is heated due to friction between the windings. While the heat generated by the wire movement is relatively small, the specific heat of the superconductor at the superconducting condition is very small, so that the superconductor at the superconducting condition is easily heated beyond the critical temperature, resulting in easy quenching.
FIG. 1 illustrates a step of winding the superconductor in a conventional method for manufacturing a superconducting magnet, from which it is seen that a length of superconductor 1 released from a reel 2 is wound on a bobbin 3 to form a winding. The coil thus wound is then immersed into a bath of a thermo-setting resin (not shown) under vacuum to vacuum-impregnate the winding. Then, the vacuum-impregnated winding is removed from the bath and heated to set the resin to firmly secure the turns of the superconductor 1 to each other and to the bobbin 3.
While this vacuum-impregnation is usually effective to rigidly secure the turns of the superconductor 1 to prevent its movement which causes heating by friction, voids 5 such as shown in FIG. 2 can be formed in a thermally-set resin 4 impregnated between the turns of the superconductors 1. When the void 5 is formed in the winding, the superconductors 1 in the void 5 are not supported and can be easily moved due to the electromagnetic force acting between the turns of the superconductors 1, resulting in a destruction of the superconducting phenomenon.
Also, the conventional method requires a very large vessel for containing a resin bath and a winding with a bobbin. Further, various equipment for establishing a vacuum such as a vacuum pump, vacuum conduits, hermetic vessel must be provided, making the facility very large, costly and complicated.